This invention relates generally to the elimination of blockage and/or distortion of radiating RF energy by an object and more particularly to a relatively simple method and apparatus which permits RF energy transmitted from a radar or communication equipment to wrap around the blockage with minimal loss in gain and relatively little destruction to the radiation pattern.
For many radar and communication applications there are often undesirable large and small metallic structures nearby which depending upon the size and location of the object and the polarization of the antenna can cause severe blockage of the RF energy radiated therefrom. Nevertheless, they are there for necessary reasons such as the tail and wings of an aircraft or the mast(s) of a ship or even the feed horn of a reflector type antenna system. In such instances a deleterious effect on antenna performance often occurs, particularly when a beam of RF energy is pointed at the object. In the past, RF energy absorbent materials have been applied to mitigate degradation of the sidelobes. However, it does little or nothing to fill in the "hole" that is caused by the blockage of the RF signal when it hits or bounces off the surface of the object.